Preparation and characterization of Al doped ZnO thin films by PLD

This paper describes the effect of doping on the composition, surface morphology and optical, structural and electrical properties of At doped ZnO thin films by pulsed laser deposition. SEM analysis shows that the crystalline nature of the deposited films decreases with an increase of At doping concentration from 1% to 6%. In the AFM analysis, the surface roughness of the deposited films increases by increasing the doping concentration of Al. At doping strongly influences the optical properties of the ZnO thin films. Optical transmittance spectra show a very good transmittance in the visible region (450-700 nm). The calculated optical band gap was found to be in the range from 3.405 to 3.464 eV. Structural analysis confirms that the increases of At concentration decrease the crystallinity of the ZnO films and the particle size decreases from 45.7 +/- 0.09 to 28.0 +/- 0.02 nm. In the Raman analysis, the active mode of Al(=1%) doped ZnO films were observed at 434.81 cm(-1). The shifts of the active mode (E-2) show the presence of tensile stress in the deposited films. The electrical properties of the deposited films showed that the values of the Hall mobility was in the range between 2.51 and 10.64 cm(2)/V s and the carrier concentration between 15.7 and 0.78 x 10(17) and the resistivity values between 1.59 and 10.97 Omega cm, depending on the doping concentration. (c) 2008 Elsevier Ltd. All rights reserved.